Polymer polyols containing halogenated aromatic monomers and polyurethane foam made therefrom

ABSTRACT

A polymer polyol is produced by a process comprising free radical polymerizing an addition polymerizable di-(substituted phenyl)monomer (e.g., methacrylic ester of diglycidylether of tetrabromobisphenol A) component in the presence of a polyol, wherein the monomer has at least one aromatic halogen and at least one aromatic ethylenically unsaturated substituent. The polymer polyol can also be made by copolymerizing said monomer with an additional ethylenically unsaturated monomer component such as styrene and acrylonitrile. Said polymer polyols are reacted with a polyisocyanate compound forming a flame retardant polyurethane foam.

FIELD OF THE INVENTION

The invention relates to polymer polyols useful in the synthesis ofpolyurethane compositions having improved flame retardancy. Inparticular, the polymer polyols are useful in making polyurethane foams.

BACKGROUND OF THE INVENTION

Polyurethanes are formed by the reaction of a polyisocyanate compoundsuch as toluene diisocyanate (TDI) and diphenylmethane diisocyanate(MDI) with a polyhydroxyl compound such as a polyol. When forming apolyurethane foam, typically water is reacted simultaneously with theisocyanate causing carbon dioxide evolution which causes the foaming ofthe polyurethane. Foams of polyurethane are widely used as cushions infurniture and automobiles.

In the manufacture of polyurethane foams, it is common to add othermaterials to increase the rate of the polyurethane reaction, enhancefoam formation and improve the resultant foam properties. For example,catalysts such as a tertiary amine or an organometallic compound may beadded to increase the reaction rate of the isocyanate with the polyol orwater. Foam formation additives may include, for example, siliconesurfactant and foam control compounds and finely divided solids such asa copolymer polyol (e.g., styrene-acrylonitrile copolymer dispersed in apolyol) which tend to lead to cell opening and, hence, typically resultsin a flexible foam. Other polyurethane foam additives includeantioxidants, stabilizers and flame retardants. Flame retardants inhibitthe burning of a polyurethane foam when ignited.

Examples of flame retardants include antimony trioxide, phosphate esterplasticizers and halogenated compounds. When the retardant is a lowmolecular weight liquid, the liquid tends to volatilize with timecausing, for example, the undesirable fogging of the windows in anautomobile. On the other hand, solid flame retardants (e.g., melamine)tend to increase the viscosity of the polyol-filler dispersion which maycause non-uniform mixing and, hence, cause nonuniform cell openingresulting in a significant density gradient in the foam from top tobottom.

U.S. Pat. Nos. 3,655,553; 3,953,393 and 4,214,055 describe polymerpolyols made by homopolymerizing a vinyl chloride or vinylidene chloridemonomer, or copolymerizing said monomer with, for example, styrene andacrylonitrile in a polyol. These materials are said to producepolyurethane foams having improved fire retardant properties. However,polymers of vinyl and vinylidene chloride are thermally unstable.Thermal decomposition of the vinyl or vinylidene chloride polymer orcopolymer evolves HCl. When forming a polyurethane foam, the evolved HCltends to deactivate the urethane catalyst and corrode the polyurethaneprocessing equipment.

U.S. Pat. No. 5,250,581 describes a polymer polyol wherein the polymeris formed from tribromostyrene and acrylonitrile. Polyurethane foamsmade with this polymer polyol are reported to have improved flameresistance compared to polyurethanes formed from conventionalstyrene-acrylonitrile polymer polyols. However, the polymer of thispolymer polyol contained large quantities of tribromostyrene. Becausetribromostyrene evolves toxic fumes when burned and it is expensive,large quantities of tribromostyrene are undesirable in a polyurethanefoam. In addition, the foams that were described all contained a secondfire retardant compound which may contribute to fogging and difficultiesin forming a uniform foam previously described.

Therefore, it would be desirable to provide a polymer polyol and apolyurethane made therefrom, the foam displaying acceptable flameretardancy while avoiding the deficiencies of the prior art justdescribed.

SUMMARY OF THE INVENTION

A first aspect of this invention is a dispersion of particles of apolymer of an addition polymerizable monomer having the structure:##STR1## wherein

j is a whole number from 0 to 4,

Z is selected from the group consisting of:

a single bond;

a substituted or unsubstituted divalent hydrocarbon radical,

a divalent radical selected from the group consisting of: S, S₂, SO,SO₂, O and CO,

X is a halogen wherein "n" is an integer from 1 to 5 and "q" is aninteger from 1 to 4,

R is a substituted or unsubstituted ethylenically unsaturatedhydrocarbon monovalent radical having:

(a)up to about 12 carbons;

(b)at least one free radical polymerizable carbon-carbon double bond,and

Y is a monovalent radical selected from the group consisting of:

hydrogen;

mercaptan;

hydroxyl and

a substituted or unsubstituted hydrocarbon monovalent radical having atmost about 12 carbons,

wherein "o" is an integer equal to 4 minus "q" and "m" is an integerequal to 5 minus "n"

in a polyol.

A second aspect of this invention is a polyurethane foam containingparticles of a polymer of an addition polymerizable monomer having thestructure: ##STR2## wherein

j is a whole number from 0 to 4,

Z is selected from the group consisting of:

a single bond;

a substituted or unsubstituted divalent hydrocarbon radical,

a divalent radical selected from the group consisting of: S, S₂, SO,SO₂, O and CO,

X is a halogen wherein "n" is an integer from 1 to 5 and "q" is aninteger from 1 to 4,

R is a substituted or unsubstituted ethylenically unsaturatedhydrocarbon monovalent radical having:

(a)up to about 12 carbons;

(b)at least one free radical polymerizable carbon-carbon double bond,and

Y is a monovalent radical selected from the group consisting of:

hydrogen;

mercaptan;

hydroxyl and

a substituted or unsubstituted hydrocarbon monovalent radical having atmost about 12 carbons,

wherein "o" is an integer equal to 4 minus "q" and "m" is an integerequal to 5 minus "n".

A polyurethane foam produced using the polymer polyol of this inventiondisplays good flame retardancy even at low halogen concentrations in thefoam and even in the absence of any other additional flame retardants.In addition, the polymer polyol may be formed and used with existingpolyurethane foam processing equipment.

DETAILED DESCRIPTION OF THE INVENTION

The polymer particles dispersed in the polyol (i.e., polymer polyol) areformed from a monomer having the structure: ##STR3## wherein Z, Y, X, Z,j, o, q, m and n are as described above.

The "Z" group of the monomer is selected from the group consisting of: asingle bond; a substituted or unsubstituted divalent hydrocarbonradical, the hydrocarbon radical being of a size which fails tosubstantially hinder the polymerization of the monomer; and a divalentradical selected from the group consisting of: S, S₂, SO, SO₂, O and CO.The "Z" group also does not participate in the free radicalpolymerization to form the polymer of the polymer polyol. When "Z" is anunsubstituted or substituted hydrocarbon radical, the radical is suchthat it does not stop the monomer from free radically polymerizing toform the polymer particles. The "Z" group of the monomer is preferably asubstituted or unsubstituted divalent hydrocarbon radical or divalentradical selected from the group consisting of: S, S₂, SO, SO₂, O and CO.More preferably "Z" is a substituted or unsubstituted divalenthydrocarbon radical. Desirably, the hydrocarbon radical has at mostabout 35 carbons. Preferably the hydrocarbon radical is a methylene,which may be substituted with a group such as CH₃, C₂ H₅, C₃ H₇, n-C₃H₇, i-C₃ H₇, cyclohexyl, bicyclo 2.2.1!heptyl, phenyl, CF₂, CF₃, CCl₃,CF₂ Cl, CN, (CH₂)₂ COOCH₃ or PO(OCH₃)₂. More preferably Z is methylenedirectly bonded to two CH₃ groups.

The monovalent radical "Y" is a monovalent radical selected from thegroup consisting of: hydrogen; mercaptan; hydroxyl and a substituted orunsubstituted hydrocarbon monovalent radical having at most about 12carbons. The monovalent radical "Y" of the monomer is preferably a grouplacking a free radical polymerizable group such as an ethylenicunsaturated bond (carbon-carbon double bond). More preferably "Y" ishydrogen, mercaptan, hydroxyl or an alkyl. Most preferably Y ishydrogen.

The "R" of the monomer is a substituted or unsubstituted ethylenicallyunsaturated hydrocarbon monovalent radical having up to about 12 carbonsand at least one free radical polymerizable carbon-carbon double bond.Preferably "R" is a monovalent linear or branched radical. Morepreferably "R" is a branched radical. Preferably the branched radicalcontains oxygen. Most preferably "R" is a methacrylic ester ofdiglycidylether which is represented by the structure: ##STR4##

The "XX" group of the monomer may be any halogen but is preferably Cl,Br or I. More preferably "X" is bromine. It is preferred that thequantity of "X" is an amount where "n" and "o" described above each areequal to 2.

The repeating units of the monomer as represented by "j" is a wholenumber from 0 to 4. Preferably "j" is 0, 2 or 4. More preferably "j" is0.

Preferred monomers include 2,2-bis(4-methacrylic ester ofdiglycidylether-3,5-diglycidylpropane, herein a methacrylic ester ofdiglycidylether of tetrabromobisphenol A (MEDTA) or oligomer thereofwhich may be represented by the structure: ##STR5## wherein "g" is aninteger from 1 to 3. The methacrylic ester of diglycidylether oftetrabromobisphenol A (MEDTA) is commercially available under thetrademark "DERAKANE 510A" of The Dow Chemical Company in a 40 weightpercent styrene-60 weight percent MEDTA solution, wherein the MEDTA is amixture of monomer ("g"=1) and oligomers ("g"=2 or 3). Another suitablemonomer is bisallylether of tetrabromobisphenol A available from GreatLakes Chemical Corp. under the trademark "BE-51".

Herein a free radical polymerizable carbon-carbon double bond may be anythat can react to form an addition polymer. The carbon-carbon doublebond may be conjugated with another carbon-carbon double bond, but it ispreferred that the double bond is unconjugated with anothercarbon-carbon double bond. Exemplary carbon-carbon double bondsubstituents of "R" may be represented by the following structures:##STR6## wherein each R' is individually hydrogen or lower alkyl (C₁-C₄). The carbon-carbon double bond may also be an ethylenic unsaturateddouble bond in a cyclic structure such as a maleimide radical having thestructure: ##STR7##

A suitable monomer may be formed by reacting a halogenateddiphenylhydroxy compound such as a bis-hydroxy-substituted-phenylcompound and one or more second compounds. The halogenated diphenylhydroxy compound can be represented by the formula: ##STR8## wherein Z,Y, X, q and o are as defined before. The bridging radical represented byZ in the above formula is preferably a carbon atom to which is bonded toone or more groups such as CH₃, C₂ H₅, C₃ H₇, n-C₃ H₇, i-C₃ H₇,cyclohexyl, bicyclo 2.2.1!heptyl, benzyl, CF₂, CF₃, CCl₃, CF₂ Cl, CN,(CH₂)₂ COOCH₃ or PO(OCH₃)₂. Preferably thebis-hydroxy-substituted-phenyl compound is a2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane referred to herein astetrabromobisphenol A. Exemplary second compounds include compoundscontaining a free radical polymerizable carbon-carbon double bond and agroup which can undergo a condensation reaction such as an epoxy,alcohol, organic acid, anhydride, aldehyde, ketone and ester.

The above suitable monomers may be formed via a condensation reactionunder conditions known in the art such as those described by U.S. Pat.Nos. 3,066,112; 3,179,623; 3,221,043; 3,256,226; 3,621,093; 3,367,992and 3,524,901, each incorporated herein by reference.

The monomer may be homopolymerized or copolymerized with one or moreadditional monomers in a polyol. Suitable additional monomers includeother ethylenically unsaturated monomers (monomers containing a freeradical polymerizable carbon-carbon double bond) which copolymerize toform copolymers with the aforementioned monomers of this invention.Representative additional monomers include aliphatic conjugated dienessuch as butadiene and isoprene; monovinylidene aromatic monomers such asstyrene, α-methyl styrene, ar-methyl styrene, ar-(t-butyl)styrene,ar-chlorostyrene, ar-cyanostyrene and ar-bromostyrene, dibromostyreneand tribromostyrene; α,β-ethylenically unsaturated carboxylic acids andesters thereof such as acrylic acid, methacrylic acid, methylmethacrylate, ethyl acrylate, 2-hydroxyethyl acrylate, butyl acrylate,itaconic acid, maleic anhydride and the like; α,β-ethylenicallyunsaturated nitriles and amides such as acrylonitrile,methacrylonitrile, acrylamide, methacrylamide, N,N-dimethylacrylamide,N-(dimethylaminomethyl)acrylamide and the like, vinyl esters such asvinyl acetate; vinyl ethers; vinyl ketones; vinyl and vinylidene halidessuch as vinylidene chloride, vinyl chloride, chlorostyrene,2,5-dichlorostyrene, bromostyrene, fluorostyrene andtrifluoromethylstyrene; and maleimide, N-arylmaleimide, andN-alkymaleimides such as maleimide, N-ethyl maleimide, as well as a widevariety of other ethylenically unsaturated materials which copolymerizewith the aforementioned di-substituted halogenated phenyl monomer, manyof which have heretofore been employed in the formation of copolymerpolyols as described in U.S. Pat. Nos. 3,823,201 and 3,383,351,incorporated herein by reference. It is understood that mixtures of twoor more of the aforementioned monomers are also suitable in making thecopolymer. Of the foregoing additional monomers, the monovinylidenearomatic monomers such as styrene and the ethylenically unsaturatednitriles such as acrylonitrile are especially preferred. Most preferablythe additional monomer is styrene, acrylonitrile or mixture thereof.

The polyol according to this invention can be a polyol such as thosedescribed in U.S. Pat. Nos. 3,383,351; 3,823,201; 4,119,586 and4,148,840, each incorporated herein by reference. Exemplary polyolsinclude polyhydroxyalkane polyols, polyoxyalkylene polyols, alkyleneoxide adducts of polyhydroxyalkanes, alkylene oxide adducts ofnon-reducing sugars and sugar derivitives, alkylene oxide adducts ofphosphorus and polyphosphorus acids, alkylene oxide adducts ofpolyphenols and polyols derived from natural oils such as caster oil.Preferably the polyols are glycols, triols or higher functionalitypolyols of poly(oxyethylene), poly(oxypropylene),poly(oxypropylene-oxyethylene) or mixtures thereof.

The polyols employed may have hydroxyl numbers which vary over a largerange, the polyols being selected based upon the desired polyurethanefoam properties that are desired. In general, the polyols can have ahydroxyl number that ranges from about 20 to about 1000. Preferably thehydroxyl number is at least about 25, and more preferably at least about30 to preferably at most about 600, and more preferably at most about450. The hydroxyl number is defined as the number of milligrams ofpotassium hydroxide required for the complete hydrolysis of the fullyacelated derivative prepared from 1 gram of polyol.

The polyol employed in producing a particular polyurethane compositionof this invention depends upon the end-use of the polyurethane productto be produced, in that the hydroxyl number is selected to result inflexible or semi-flexible foams or elastomers when the polymer polyolproduced from the polyol is converted to a polyurethane. The polyolspreferably possess a hydroxyl number of from about 50 to about 150 forsemi-flexible foams and from about 20 to about 70 for flexible foams.Mixtures of polyols can be used.

The polymer polyol may be produced by polymerizing the monomer in thepresence of a polyol by methods known in the art such as those describedin U.S. Pat. Nos. 4,104,236; 3,823,201; 4,148,840; 4,652,589; 4,390645;3,833,641 and 4,242,476, each incorporated herein by reference.

The polymer polyol of this invention may be prepared from an amount ofthe monomer from 0.5 to 100% by weight of the total amount of monomer.Desirably, the amount of said monomer is at most 50% by weight of thetotal amount of monomer. Preferably the amount of said monomer is atmost about 20%, more preferably at most about 15%, and most preferablyat most about 12% to at least about 0.5%, preferably at least about 1%,and more preferably at least about 2% by weight of the total amount ofmonomer.

When forming the polymer polyol it is advantageous to polymerize in thepresence of a polymerization initiator. Representative initiatorsinclude free radical vinyl polymerization initiators such as peroxides,persulfates, perborates, percarbonates and azo compounds. Specificexamples include 2,2'-azo-bis-isobutyonitrile (AIBN), dibenzoylperoxide, lauroyl peroxide, di-t-butyl peroxide, diisopropyl peroxidecarbonate, t-butyl peroxy-2-ethylhexonoate, t-butylperoxypivalate,2,5-dimethyl-hexane-2,5-di-peroxy-2-ethyl hexoate,t-butylperoxyneodeconate, t-butylperoxybenzoate, t-butylperoxycrotonate, t-butyl peroxyisobutyrate, di-t-butylperoxyphthalateand 2,2'-azo-bis(methylbutanenitrile). When the monomers are styrene,acrylonitrile and the di-substituted halogenated phenyl monomer, theinitiator is preferably 2,2'-azo-bis(methylbutanenitrile), commerciallyavailable under the trademark "VAZO 67" of E. I. Du Pont De Nemours andCo. The initiator is desirably added in an amount sufficient to initiatepolymerization. Typically, the amount of initiator ranges from about 0.4to about 1.2% by weight of all of the monomers.

The polymer polyol may also be formed in the presence of other additivessuch as an organic solvent, chain transfer agent, stabilizer and flameretardants, all of which are common in the art. An example of a solventis toluene. Exemplary chain transfer agents include dodecylmercaptan andisopropyl alcohol. Preferably the chain transfer agent isdodecylmercaptan. Stabilizers may be used to increase the polymercontent in the polyol, while the polymer polyol still has a lowviscosity and acceptable resistance to polymer sedimentation.Stabilizers typically are polyether polyols that have deliberately addedunsaturation and thus, can be grafted onto the growing polymer chains ofthe polymer of the polymer polyol. Exemplary stabilizers include thosedescribed in U.S. Pat. Nos. 4,883,832; 4,198,488 and 3,823,201, eachincorporated herein by reference. Exemplary flame retardants includeantimony trioxide, phosphate ester plasticizers and halogenatedcompounds other than the di-substituted halogenated phenyl monomer. Eventhough flame retardants may be included in the polymer polyol orpolyurethane made therefrom, it is preferred that no additional flameretardant is used.

Typically, the temperature of the reaction is dependent on the half lifeof the initiator used in forming the polymer polyol and thedecomposition temperature of the polymer polyol made or components usedto make the polymer polyol. Typically, the temperature is a temperaturethat results in the half life of the initiator that is shorter thanabout 6 minutes and preferably at most about 2 to 3 minutes. Generally,the temperature is typically at least about 60° C., preferably at leastabout 80° C., and more preferably at least about 100° C. to preferablyat most about 150° C., more preferably at most about 140° C., and mostpreferably at most about 135° C.

The time of reaction may be varied over a wide range depending on thedesired polyol properties such as viscosity. Generally, longer timesresult in higher product viscosities. Preferably the time is at leastabout 5 minutes, more preferably at least about 10 minutes, and mostpreferably at least about 12 minutes to preferably at most about 6hours, more preferably at most about 5 hours, and most preferably atmost about 4 hours.

The pressure of the reaction may be varied over a large range andpressure in excess of ambient or atmospheric is typically used to limitthe volatilization of the components in the reaction mixture. Thepressure is desirably at least atmospheric or ambient pressure andpreferably at least about 0.05 MPa, and more preferably at least about0.10 MPa to preferably at most about 1.0 MPa, and more preferably atmost about 0.6 MPa. The polymer polyol may be formed by a continuous,batch, or semi-batch process wherein the monomers are polymerized at theabove conditions. Also, the reaction is desirably carried out in anatmosphere inert to the reactants such as nitrogen.

The solids content, viscosity, and particle size of the polymer polyolthat is formed may vary over a wide range depending on the desiredproperties of the polymer polyol and desired properties of apolyurethane made therefrom. The polymer polyol that is formed typicallyhas a solids content (i.e., weight of the particles of polymer) of atleast about 1% to about at most about 70% by weight of the total weightof the polymer polyol. Preferably the solids content is at least about8%, and more preferably at least about 10% to preferably at most about60%, and more preferably at most about 55% by weight of the total weightof the polymer polyol. The polymer polyol typically has a viscosity ofat most about 20,000, preferably at most about 10,000, and morepreferably at most about 7000 mPas (milliPascal-seconds). The particlesdesirably have a particle size between about 0.1 to about 100 microns indiameter. Preferably the volume average particle size is greater thanabout 0.15, more preferably greater than about 0.2, and most preferablygreater than about 0.25 to preferably less than about 60, morepreferably less than about 50, and most preferably less than about 10microns in diameter.

When forming a polyurethane foam according to this invention, the foamcan be formed by any convenient method, wherein the polymer polyol ofthis invention is reacted with an organic polyisocyanate in the presenceof a blowing agent such as water resulting in the desired polyurethanefoam. The foam may be formed by known techniques such as prepolymer(described in U.S. Pat. No. 4,390,645), one shot (described in U.S. Pat.No. 2,866,744) or frothing (described in U.S. Pat. Nos. 3,755,212;3,849,156 and 3,821,130), each of the aforementioned patentsincorporated herein by reference. The method to produce the foam may becarried out in the presence of catalysts, surface active agents, chainextending agents, fillers such as calcium carbonate, pigments such astitanium dioxide, iron oxide, chromium oxide, azo/diazo dyes,phthalocyanines, dioxazines and carbon black and additional polyols. Thefoam of this invention is preferably a flexible foam.

The organic polyisocyanate may be an aromatic or aliphaticpolyisocyanate, polymeric isocyanate, aromatic diisocyanate andaliphatic diisocyanate. Exemplary polyiisocyanates include m-phenylenediisocyanate, tolylene-2-4-diisocyanate, tolylene-2-6-diisocyanate,hexamethylene-1,6-diisocyanate, tetramethylene-1,4-diisocyanate,cyclohexane-1,4-diisocyanate, hexahydrotolylene diisocyanate,naphthylene-1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate,diphenylmethane-4,4'-diisocyanate, 4,4'-biphenylene diisocyanate,3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4-4'-biphenyldiisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate,4,4',4"-triphenyl methane triisocyanate, polymethylenepolyphenylisocyanate and tolylene-2,4,6-triisocyanate,4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate. Preferably thepolyisocyanate is diphenylmethane-4,4'-diisocyanate (MDI),tolylene-2-4-diisocyanate, tolylene-2-6-diisocyanate or mixturesthereof. Tolylene-2-4-diisocyanate, tolylene-2-6-diisocyanate andmixtures thereof are generically referred to as TDI.

The amount of polyisocyanate used in making polyurethane is commonlygiven by the isocyanate index. The isocyanate index can be given by theequation: ##EQU1## The theoretical equivalent amount of isocyanate isthe stoichiometric amount of isocyanate required to react with thepolyol and any other reactive additives such as water. The isocyanateindex may be varied over a range to affect properties of a foam that isproduced. Generally, a higher index produces a harder foam which isthought to be due to increased covalent cross-linking of isocyanatereactive sites. In the production of flexible slabstock foams, theisocyanate index typically ranges from about 105 to 115. In moldedflexible foams, the isocyanate index typically ranges from about 85 toabout 110.

The blowing agent may be water, a low boiling hydrocarbon such aspentane, hexane, heptane, pentene, and heptene, directly added carbondioxide, an azo compound such as azohexahydrobenzodnitrile or ahalogenated hydrocarbon such as dichlorodifluoroethane, vinylidenechloride and methylene chloride.

In the formation of the polyurethane foam, it may be desirable to reactthe polyisocyanate and polymer polyol in the presence of a catalyst. Thecatalyst may catalyze the polyol-isocyanate or water-isocyanatereaction. Representative catalysts include:

(a) tertiary amines such as trimethylamine, triethylamine,N-n-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine,N,N-dimethylethanolamine, N,N,N',N'-tetramethyl-1,4-butanediamine,N,N-dimethylpiperazine, 1,4-diazobicyclo 2,2,2!octane,bis(dimethylaminoethyl)ether and triethylenediamine;

(b) tertiary phosphines such as trialkylphosphines anddialkylbenzylphosphines;

(c) chelates of various metals such as those which can be obtained fromacetylacetone, benzoylacetone, trifluoroacetyl acetone, ethylacetoacetate and the like with metals such as Be, Mg, Zn, Cd, Pd, Ti,Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co and Ni;

(d) acidic metal salts of strong acids such as ferric chloride, stannicchloride, stannous chloride, antimony trichloride, bismuth nitrate andbismuth chloride;

(e) strong bases such as alkali and alkaline earth metal hydroxides,alkoxides and phenoxides;

(f) alcoholates and phenolates of various metals such as Ti(OR)₄,Sn(OR)₄ and Al(OR)₃, wherein R is alkyl or aryl and the reactionproducts of the alcoholates with carboxylic acids, Beta-diketones and2-(N,N-dialkylamino)alcohols;

(g) salts of organic acids with a variety of metal such as alkalimetals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni and Cu including,for example, sodium acetate, stannous octoate, stannous oleate, leadoctoate, metallic driers such as manganese and cobalt naphthenate;

(h) organometallic derivatives of tetravalent tin, trivalent andpentavalent As, Sb and Bi and metal carbonyls of iron and cobalt and

(i) mixtures thereof.

Catalysts are typically used in small amounts, for example, eachcatalyst being employed from about 0.0015 to about 5% by weight of thepolyurethane reaction mixture (i.e., all of the components used to makethe foam).

When forming a foam, a surface active agent is commonly incorporatedinto the reactant mixture to stabilize the rising foam, lower bulksurface tension, emulsification of incompatible components in thereactant mixture and counteract the defoaming effect of any solids addedto or formed during the foam reaction. Examples of surface active agentsinclude nonionic surfactants and wetting agents such as those preparedby the sequential addition of propylene oxide and then ethylene oxide topropylene glycol, the solid or liquid organosilicones, polyethyleneglycol ethers of long chain alcohols, tertiary amine or alkylolaminesalt of long chain alkyl acid sulfate esters, alkyl sulfonic ester andalkyl arylsulfonic acids. The surface active agents prepared by thesequential addition of propylene oxide and then ethylene oxide topropylene glycol and the solid or liquid organosilicones are preferred.Liquid organosilicones which are not hydrolyzable are more preferred.Examples of non-hydrolyzable organosilicones include those availableunder the trademarks "DOW CORNING 5043," "DOW CORNING 5169" and "DOWCORNING 5244," available from Dow Corning Corp., and "Y-10515,"available from Union Carbide Corp. Surface active agents are typicallyused in small amounts, for example, from about 0.0015 to about 5% byweight of the polyurethane reaction mixture (i.e., all of the componentsused to make the foam).

Chain extending agents may be used in the formation of the polyurethanefoam. Examples include those compounds which have at least two activehydrogen groups such as primary and secondary aliphatic or aromaticmonoamines or diamines. Representative amines include diethanolamine,monoethanolamine, phenylene diamine, bis(3-chloro-4-aminophenyl)methane,2,4-diamino-3,5-diethyl toluene, trisecondary butanolamine,isopropanaolamine, diisopropanolamine,N-(2-hydroxypropyl)ethylenediamine andN,N'-di(2-hydroxypropyl)ethylenediamine.

The additional polyol can be any one of the previously describedpolyols.

The polyurethane foam desirably has a halogen concentration derived fromthe di-substituted halogenated phenyl monomer of at most about 10%,preferably at most 3%, more preferably at most 2%, and most preferablyat most about 1% to greater than 0%, preferably greater than about0.05%, more preferably greater than 0.1%, and most preferably greaterthan about 0.15% by weight of the foam. Preferably the halogen ischlorine, bromine, iodine or mixture thereof. More preferably thehalogen is bromine. Halogens may be incorporated into the foam fromadditional halogenated monomers present in the polymer polyol such aschlorostyrene, dichlorostyrene, bromostyrene or by halogen containingfire retardants added to the foam. The total halogen concentration ofthe foam can be determined by atomic flame emission, atomic absorption,atomic fluorescence or atomic emission spectroscopy described inInstrumental Methods of Analysis, H. H. Willard, et al., Wadsworth Pub.Co., pp. 127-176, 1981, incorporated herein by reference.

MVSS-302 flammability test is a timed burn test of a polyurethane foamslab which is 0.5" thick×4" wide×14" long. A flame burning normal to theplane defined by the width and length of the slab is placed under oneend of the slab and the burn rating is assessed. The burn rate iscalculated on the time it takes the flame to travel a distance along thelength of the slab. There are 5 ratings of the polyurethane in the test:

(1) DNI: Does not ignite,

(2) SE: (Self extinguishing) ignites but does not burn past 1.5 inchesfrom the flame end during the test,

(3) SE/NBR602: ignites but stops burning within 60 seconds after thefoam burns past 1.5 inches from the ignited end and the foam burns lessthan 3.5 inches from the ignited end,

(4) SE/Bx: burns greater than 60 seconds and more than 3.5 inches fromthe ignited end but extinguishes before burning 13.5 inches from theignited end (x=burn rate "distance/min"), and

(5) Bx: burns 13.5 inches from the ignited end.

The foam desirably has a flammability rating which is as good or betterthan a "Bx" of 100 mm/min as required by Fed. Reg. 38 No. 5 3-3, Nov. 6,1973, for automotive seating. Preferably the foam has a rating ofSE/NBR602, more preferably a rating of SE, and most preferably a ratingof DNI. The numerical flame spread rating described herein is notintended to reflect hazards presented by this or any other materialunder actual fire conditions.

EXAMPLES Preparation of Copolymer Polyol

Example 1

The polymer polyol of this example is made using a reactor equipped witha thermocouple, temperature control, stirrer and a feed port. Thereaction is carried out under a nitrogen atmosphere at a temperature ofabout 125° C. and at a pressure ranging from about 275 to about 325 kPa.The reactants and products are constantly agitated throughout thereaction. Initially, the reactor, which is at room temperature, ischarged with 1075 parts by weight (pbw) polyol A (glycerine initiatedblock polyether polyol which is formed from 86% by weight propyleneoxide (PO) and 14% by weight ethylene oxide (EO), the polyol having anOH number of about 37.4 mg KOH/g) and 75 pbw of stabilizer (thecondensation product of 1 mole of vinyl trimethoxysilane and 3 moles ofa glycerine initiated block polyether polyol formed from 87% by weightPO and 13% by weight EO and having an OH number of about 47.9 mg KOH/g)This initial charge is then heated to the reaction temperature (i.e.,125° C.). A slurry of 11.4 ppw VAZO 67 initiator(2,2'-azo-bis(2-methylbutanenitrile), available from E. I. Dupont deNemours and Co. in 650 ppw polyol A, is then fed into the reactor at arate of about 3.4 pbw/min. After the VAZO slurry has been fed into thereactor for about 2 minutes, a monomer feed consisting of about 600 pbwstyrene, 480 pbw acrylonitrile, 120 pbw DERAKANE 510A and 36 pbwdodecylmercaptan is fed into the reactor at a rate of about 13.7 pbw/minuntil exhausted (i.e., about 90 minutes). 120 pbw of DERAKANE 510A isequivalent to adding about 70 pbw of MEDTA. Once the monomer feed hasbeen exhausted, the feed rate of the VAZO slurry is raised to about 8.2pbw/min until exhausted (total feed time of VAZO slurry is about 135minutes). After finishing feeding the VAZO slurry, residual monomers arestripped by applying a vacuum to the reactor for three hours whilemaintaining the temperature at 125° C. The polymer polyol formed issubsequently cooled to room temperature and removed from the reactor.

The polymer polyol of this example has a viscosity of 5800 mPas asmeasured by a Brookfield viscometer using a LV-3 spindle at 12 RPM, asolids content of 40.6% by weight as measured by a Praxis pulsed NMR anda volume average particle size of 0.5 micrometer in diameter as measuredby Horiba LA-500 particle size analyzer. The halogen content of thepolymer polyol is about 1% by weight of the polymer polyol.

Example 2

A polymer polyol is made by the same procedure described in Example 1except the amounts of materials used are different and the DERAKANE 510Ais separately added to the reactant mixture after the styrene andacrylonitrile had already been added for approximately 30 minutes. Thestyrene and acrylonitrile feed continues with the DERAKANE 510A feed.The amount of components and properties of the polymer polyol of Example2 are also shown in Table 1.

Example 3

A polymer polyol is made by the same procedure as described in Example 1except that bisallylether tetrabromobisphenol A is used instead of theDERAKANE 510A and the amounts of materials employed are different asshown in Table 1. The amount of components and properties of thispolymer polyol are also shown in Table 1.

Comparative Example 1

A polymer polyol is made by the same procedure as described in Example 1except that dibromostyrene is used instead of DERAKANE 510A and theamounts of materials employed are different as shown in Table 1. Thecomponent amounts and properties of this polymer polyol are also shownin Table 1.

Comparative Example 2

A polymer polyol is made by the same procedure as described in Example 1except that pentabromobenzylacrylate is used instead of DERAKANE 510Aand the amounts of materials employed are different as shown in Table 1.The component amounts and properties of this polymer polyol are alsoshown in Table 1.

Preparation of Polyurethane Foams

Example 4

About 30 pbw of the Example 1 polymer polyol is mixed with about 70 pbwof a polyol B (sucrose and glycerine initiated formed from 86% by weightPO and 14% by weight EO cap and having a hydroxyl (OH) number of about32.6 mg KOH/g polyol and a functionality of about 3.4) which results ina polymer polyol dispersion having a polymeric solids content of about12 parts by weight per hundred parts by weight of total polyol (12 pph).The following components are then added to the polymer polyol dispersionin parts per hundred of total polyol (pph):

(1)0.5 pph DOW CORNING 5043 silicone surfactant,

(2)0.5 pph DOW CORNING 5169 silicone surfactant,

(3)2.0 pph diethanolamine,

(4)0.15 pph DABCO 33-LV catalyst (33% triethylene diamine in dipropyleneglycol) available from Air Products and Chemicals Inc.,

(5)0.08 pph NIAX A-1 catalyst (70% bis(dimethylaminoethylether) and 30%dipropylene glycol) available from Union Carbide Corp.,

(6)0.60 pph NIAX A-4 catalyst available from Union Carbide Corp. and

(7)3.90 pph water.

The above blended polymer polyol (BPP) is reacted with an amount oftoluene diisocyanate (TDI), available under the trademark "VORANATE T80"of The Dow Chemical Company, equivalent to an isocyanate index of 95.The BPP and TDI are mixed and reacted using a Hi-Tech RCM 30, a highpressure metering and mixing foam machine manufactured by Hi-TechEngineering, Inc. of Grand Rapids, MI, wherein the blended polymerpolyol and toluene diisocyanate are delivered to a high pressureimpingement mix-head at a pressure of 13-14 MPa. The BPP and TDI beforeand at the mix-head are maintained at about 23° C. The TDI and BPP afterbeing mixed in the mix-head are poured into a 38 cm×38 cm×11 cm moldmaintained at 68° C. Prior to filling, the mold is sprayed with ChemTrend release agent PRC-7166. Foams are demolded 4.5 minutes afterfilling of the mold and then are crushed through rollers once to 5.1 cmand once more to 2.5 cm. Foams are aged for 5 days and, subsequently,burn tested using the MVSS 302 method. None of the foam samples ignited(DNI) as per the MVSS 302 test method.

Example 5

The polyurethane of this example is made by the same procedure describedin Example 4 except that an isocyanate index of 105 is used. None of thefoam samples ignited (DNI) as per the MVSS 302 test method.

Example 6

The polyurethane of this example is made by the same procedure describedin Example 4 except that the polymer polyol of Example 2 is used. Noneof the foam samples ignited (DNI) as per the MVSS 302 test method.

Example 7

The polyurethane of this example is made by the same procedure describedin Example 6 except that an isocyanate index of 105 is used. None of thefoam samples ignited (DNI) as per the MVSS 302 test method.

Example 8 (a) and (b)

The polyurethane of this example is made by the same procedure describedin Example 4 except that the polymer polyol of Example 3 is used. Theisocyanate index of Example 8(a) is 95 and the index for Example 8(b) is105. The combined results of 8(a) and (b) are referred to herein asExample 8 and are as follows: about 60% of the foam samples did notignite (DNI) as per the MVSS 302 test method. All of the samples had arating of SE/NBR602 or better.

Comparative Example 3

The polyurethane of this example is made by the same procedure describedin Example 4 except that the polymer polyol of Comparative Example 1 isused and the isocyanate index is 105. About 50% of the foam samples didnot ignite (DNI) as per the MVSS 302 test method. About 80% of thesamples had a rating of SE/NBR602 or better.

Comparative Example 4

The polyurethane of this example is made by the same procedure describedin Example 1 except that the polymer polyol of Comparative Example 2 isused and the isocyanate index is 105. About 80% of the foam samples didnot ignite (DNI) as per the MVSS 302 test method. About 90% of thesamples had a rating of SE/NBR602 or better.

The results of these tests show that the polyurethanes made using thepolymer polyols of this invention have surprisingly improved flameretardancy at reduced halogen (i.e., bromine) levels than thecomparative examples. For example, the polyurethane foam of Example 5displays improved flame retardancy compared to the polyurethane foam ofComparative Examples 3 and 4, even though the foam of Example 5 containsabout half the amount of bromine present in the polyurethane foam ofComparative Examples 3 and 4. Also, the polyurethane foam of Example 8has a better overall burn rating (all pass SE/NBR602) than the foams ofComparative Examples 3 and 4, even though the polymer polyol used tomake the foam of Example 8 had a high viscosity and a halogen contentlower than the polymer polyols used to make the foams of ComparativeExamples 3 and 4.

                  TABLE 1                                                         ______________________________________                                                                           Comp. Comp.                                Example #      1      2*     3     1     2                                    ______________________________________                                        Monomer                                                                       Ratios, Wt %                                                                  Styrene        50     52     56    54    55                                   Acrylonitriie  40     40     38    40    40                                   DERAKANE 510A  10     8                                                       Bisallylether                6                                                Tetrabromobisphenoi A                                                         Dibromostyrene                     6                                          Pentabromobenzylacrylate                 5                                    Monomer Feed, min.                                                                           90     90     73    64    68                                   Monomer Feed, (pbw)                                                           Styrene        600    499    672   648   660                                  Acrylonitriie  480    384    451   480   480                                  DERAKANE 510A  120    77                                                      Bisallylether                72                                               Tetrabromobisphenoi A                                                         Dibromostyrene                     72                                         Pentabromobenzylacrylate                 60                                   VAZO Slurry (pbw)                                                             VAZO 67        11.4   9.1    11.4  11.4  11.4                                 Polyol A       650    520    650   650   650                                  Dodecylmercaptan                                                                             36     16     12    12    12                                   Initial                                                                       Reactor Charge, (pbw)                                                         Polyol A       1075   1445   1112  1112  1075                                 Stabilizer     75     75     38    38    75                                   Copolymer                                                                     Polyol Properties                                                             Solids Content, Wt %                                                                         40.6   34.4   41.0  40.0  40.9                                 Viscosity, mPas                                                                              5800   4100   17000 5130  5500                                 Mean Particle Size, μ                                                                     .52    .44    .50   .51   .40                                  Bromine concentration wt. %                                                                  0.8%   0.6%   1.3%  1.5%  1.6%                                 ______________________________________                                         *Note Monomer feed in this example only includes Styrene and                  Acrylonitrile; DERAKANE is added separately as described herein.         

What is claimed is:
 1. A polyurethane foam containing particles of apolymer of an addition polymerizable monomer having the structure:##STR9## wherein j is a whole number from 0 to 4,Z is selected from thegroup consisting of:a single bond; a substituted or unsubstituteddivalent hydrocarbon radical, a divalent radical selected from the groupconsisting of: S, S₂, SO, SO₂, O and CO, X is a halogen wherein "n" isan integer from 1 to 5 and "q" is an integer from 1 to 4, R is asubstituted or unsubstituted ethylenically unsaturated hydrocarbonmonovalent radical having:(a) up to about 12 carbons; (b) at least onefree radical polymerizable carbon-carbon double bond, and Y is amonovalent radical selected from the group consisting of:hydrogen;mercaptan; hydroxyl and a substituted or unsubstituted hydrocarbonmonovalent radical having at most about 12 carbons, wherein "o" is aninteger equal to 4 minus "q" and "m" is an integer equal to 5 minus "n"and said polyurethane foam is comprised of the reaction product of apolyol having said particles suspended therein and an organicpolyisocyanate, wherein said reaction product is formed in the presenceof a blowing agent.
 2. The foam of claim 1 wherein X is chlorine,bromine, iodine or mixtures thereof.
 3. The foam of claim 2 wherein X isbromine.
 4. The foam of claim 1 wherein Z is methylene or a methylenesubstituted with a radical selected from the group consisting of: CH₃,C₂ H₅, C₃ H₇, n-C₃ H₇, i-C₃ H₇, cyclohexyl, bicyclo 2.2.1!heptyl,phenyl, CF₂, CF₃, CCl₃, CF₂ Cl, CN, (CH₂)₂ COOCH₃ and PO(OCH₃)₂.
 5. Thefoam of claim 4 wherein the methylene is substituted with two CH₃monovalent radicals.
 6. The foam of claim 1 wherein R is a monovalentlinear or branched radical.
 7. The foam of claim 6 wherein R is abranched radical.
 8. The foam of claim 7 wherein the branched radicalcontains oxygen.
 9. The foam of claim 8 wherein the branched radical ismethacrylic ester of diglycidylether represented by the structure:##STR10##
 10. The foam of claim 1 wherein the monomer is methacrylicester of diglycidylether of tetrabromobisphenol A.
 11. The foam of claim1 wherein the polymer is a copolymer of the monomer and a copolymermonomer.
 12. The foam of claim 11 wherein the copolymer monomer isstyrene, acrylonitrile or a mixture thereof.
 13. The foam of claim 11wherein X is chlorine, bromine, iodine or mixtures thereof.
 14. The foamof claim 13 wherein X is bromine.
 15. The foam of claim 11 wherein Z ismethylene or a methylene substituted with a radical selected from thegroup consisting of: CH₃, C₂ H₅, C₃ H₇, n-C₃ H₇, i-C₃ H₇, cyclohexyl,bicyclo 2.2.1!heptyl, phenyl, CF₂, CF₃, CCl₃, CF₂ Cl, CN, (CH₂)₂ COOCH₃and PO(OCH₃)₂.
 16. The foam of claim 15 wherein the methylene issubstituted with two CH₃ monovalent radicals.
 17. The foam of claim 11wherein R is a monovalent linear or branched radical.
 18. The foam ofclaim 17 wherein R is a branched radical.
 19. The foam of claim 18wherein the branched radical contains oxygen.
 20. The foam of claim 19wherein the branched radical is methacrylic ester of diglycidyletherrepresented by the structure: ##STR11##
 21. The foam of claim 11 whereinthe monomer is methacrylic ester of diglycidylether oftetrabromobisphenol A.
 22. The foam of claim 12 wherein the monomer ismethacrylic ester of diglycidylether of tetrabromobisphenol A.
 23. Thefoam of claim 1 wherein the foam has a burn rating of SE or better asdetermined by MVSS-302 and a halogen content of at most 2% by weight ofthe foam.
 24. The foam of claim 23 wherein the halogen content isentirely from the monomer.
 25. The foam of claim 11 wherein the foam hasa burn rating of SE or better as determined by MVSS-302 and a halogenconcentration of 2% by weight of the foam.
 26. The foam of claim 25wherein the halogen content is entirely from the monomer.